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How to access Qt GUI from an library using qt designer form

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  • mrjjM mrjj

    @Srujan said in how to access Qt GUI from an library using qt designer form:

    @mrjj
    Actually in our case we are using some standard applications like cryptokimanager e.t.c..

    Meaning that there should not be any globals variables?
    Try google
    "QWidget: Must construct a QApplication before a QWidget"
    and you see there are various reason for this message.

    Most often the use of "extern" or static variables.

    S Offline
    S Offline
    Srujan
    wrote on last edited by
    #12

    @mrjj
    Through normal application I am able to invoke QT GUI part.
    Here my application code..

    //
    //main.cpp
    //
    #include <QCoreApplication>
    #include"helper.h"
    #include <QtWidgets/QApplication>
    
    int main(int argc, char *argv[])
    {
        QApplication a(argc, argv); // previously its like QCoreApplication
    
        show_dialog1( );
    
        return a.exec();
    }
    
    //changes in .pro file
    QT       += gui
    
    greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
    

    After these changes in application project, able to invoke GUI part in shared library

    But through our standard applications not able to invoke.

    Any idea-
    That what changes required for such applications....!!

    Any way thanks for your support....

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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #13

      Hi,

      What are your "standard application" ?

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

      S 1 Reply Last reply
      2
      • SGaistS SGaist

        Hi,

        What are your "standard application" ?

        S Offline
        S Offline
        Srujan
        wrote on last edited by
        #14

        @SGaist
        Its "cryptokimanager"

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        0
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #15

          Let me rephrase that: what toolkit does it use ?

          Is it already using Qt ?

          Are you building that app yourself or are you writing a plugin for it and have no access to its internals ?

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          S 1 Reply Last reply
          0
          • SGaistS SGaist

            Let me rephrase that: what toolkit does it use ?

            Is it already using Qt ?

            Are you building that app yourself or are you writing a plugin for it and have no access to its internals ?

            S Offline
            S Offline
            Srujan
            wrote on last edited by Srujan
            #16

            @SGaist
            Its a tool for managing and validating a pkcs#11 module..
            For more info please refer Cryptoki manager

            1 Reply Last reply
            0
            • VRoninV Offline
              VRoninV Offline
              VRonin
              wrote on last edited by
              #17

              Can you post your code from which you call show_dialog1( ); ?

              "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
              ~Napoleon Bonaparte

              On a crusade to banish setIndexWidget() from the holy land of Qt

              S 1 Reply Last reply
              1
              • VRoninV VRonin

                Can you post your code from which you call show_dialog1( ); ?

                S Offline
                S Offline
                Srujan
                wrote on last edited by
                #18

                @VRonin
                simply I have called 'show_dialog1();' from one of exported functions in shared library..

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                • VRoninV Offline
                  VRoninV Offline
                  VRonin
                  wrote on last edited by VRonin
                  #19

                  I suspect you are not creating the application. try Q_ASSERT(QCoreApplication::instance()); if it asserts (i.e. instance() returns NULL) then it means you simply forgot to crate the QApplication before creating any QWidget

                  "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                  ~Napoleon Bonaparte

                  On a crusade to banish setIndexWidget() from the holy land of Qt

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                  0
                  • SGaistS Offline
                    SGaistS Offline
                    SGaist
                    Lifetime Qt Champion
                    wrote on last edited by
                    #20

                    The question you are not answering is: are you working on that software code source directly ?

                    Interested in AI ? www.idiap.ch
                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                    S 1 Reply Last reply
                    1
                    • SGaistS SGaist

                      The question you are not answering is: are you working on that software code source directly ?

                      S Offline
                      S Offline
                      Srujan
                      wrote on last edited by
                      #21

                      @SGaist
                      yes

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                      • SGaistS Offline
                        SGaistS Offline
                        SGaist
                        Lifetime Qt Champion
                        wrote on last edited by
                        #22

                        Ok, then are you converting it to a full-blown Qt application ?

                        Interested in AI ? www.idiap.ch
                        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                        S 1 Reply Last reply
                        0
                        • SGaistS SGaist

                          Ok, then are you converting it to a full-blown Qt application ?

                          S Offline
                          S Offline
                          Srujan
                          wrote on last edited by
                          #23

                          @SGaist
                          If you are talking about- Cryptoki manager then i am not working on that application. I working on the library that is used to test with cryptokimanager(thrid party standard application).
                          As specified earlier, in my library there is a need of dialog part.

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                          • SGaistS Offline
                            SGaistS Offline
                            SGaist
                            Lifetime Qt Champion
                            wrote on last edited by
                            #24

                            So you are going to call the Cryptoki manager application from your code ?

                            Interested in AI ? www.idiap.ch
                            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                            S 1 Reply Last reply
                            0
                            • SGaistS SGaist

                              So you are going to call the Cryptoki manager application from your code ?

                              S Offline
                              S Offline
                              Srujan
                              wrote on last edited by
                              #25

                              @SGaist
                              yes

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                              • SGaistS Offline
                                SGaistS Offline
                                SGaist
                                Lifetime Qt Champion
                                wrote on last edited by
                                #26

                                What's still not clear is whether you are writing a full-blown Qt application for that. Is it the case ?

                                Interested in AI ? www.idiap.ch
                                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                S 1 Reply Last reply
                                0
                                • SGaistS SGaist

                                  What's still not clear is whether you are writing a full-blown Qt application for that. Is it the case ?

                                  S Offline
                                  S Offline
                                  Srujan
                                  wrote on last edited by
                                  #27

                                  @SGaist yes now i have created separate qt application and invoking that application from library using pipe mechanism..
                                  Now the issue is 'getting value from that application(what ever entered in qlineedit of dialog box)'

                                  jsulmJ 1 Reply Last reply
                                  0
                                  • S Srujan

                                    @SGaist yes now i have created separate qt application and invoking that application from library using pipe mechanism..
                                    Now the issue is 'getting value from that application(what ever entered in qlineedit of dialog box)'

                                    jsulmJ Offline
                                    jsulmJ Offline
                                    jsulm
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #28

                                    @Srujan Your Qt application could write to stdout and your library would read stdout of that application and parse it. See the documentation for QProcess.

                                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                                    S 1 Reply Last reply
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                                    • jsulmJ jsulm

                                      @Srujan Your Qt application could write to stdout and your library would read stdout of that application and parse it. See the documentation for QProcess.

                                      S Offline
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                                      Srujan
                                      wrote on last edited by
                                      #29

                                      @jsulm Thanks it worked..

                                      1 Reply Last reply
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